This invention relates generally to laser scanning apparatus and more particularly to compact, self-contained laser scanners.
Various hand-held, laser scanning apparatus have been disclosed in the patent literature and many are commercially available to read bar codes, e.g., the uniform product code, which is imprinted on packaging for product, or on the product itself or on some other item.
Hand-held scanning devices typically are composed of a relatively small, light weight, scanning head for projecting a scan pattern onto a bar code to read the that code. For example, in U.S. Pat. No. 4,575,625, of which I am the inventor, and which is assigned to the same assignee as this invention, there is disclosed a hand-held laser scanner. That scanner is a completely self-contained unit in that it includes laser scanning means and power supplies, a decoding computer to provide a signal indicative of the information contained in the bar code, and communication capabilities to enable the uploading/ downloading of data to and from the scanner. Thus, the scanner includes, among other things, a laser tube and an associated optic bench assembly. The laser tube produces a laser beam which is directed to a rotating reflective polygon. The polygon is rotated by an associated motor assembly. The laser beam is swept by the rotating polygon through a pre-determined arc and is directed out through a window in the housing to sweep across a bar code located opposite the window. A photo detector located within the housing receives the light reflected off of the bar code and converts that light into an electrical signal which is amplified and processed by an associated amplifier and signal processing circuitry, also located within the scanner. The scanner also includes a low voltage power supply, a microprocessor and associated circuitry, a high voltage power supply, a releasable input/output cable connector or plug, an associated input/output cable, and an on/off trigger assembly. The housing for the scanner basically comprises a molded plastic body having a cylindrical hand-grip portion and a finger opening located therebelow. The shape of the housing is shown in U.S. Design Pat. No. D281,977, also assigned to the same assignee as this invention.
In my co-pending U.S. Pat. No. 4,805,175, entitled Ultra Compact, Hand-Held Laser Scanner, which is assigned to the same assignee as this invention, there is disclosed an even more compact hand-held scanner. That scanner basically comprises a laser tube and associated high voltage power assembly (or in an alternative embodiment a semi-conductor laser diode and associated supply and control means), beam folding and sweeping optics, a motor sub-assembly, a photo detector and associated amplification and signal processing circuit sub-assembly, a releasable input/output cable connector or plug, an associated input/output cable, and an on/off trigger assembly, all housed within an extremely compact and ergonomically designed housing. The housing includes a short snout or body portion in which a window through which the laser beam and the reflected light passes, and a supporting, hand-grip portion arranged to be held within the user's hand. The housing's construction enhances the balance point of the device by putting its center of gravity in the operator's hands so that it can be held comfortably for long periods of time without operator fatigue.
In the interest of compactness the device of my copending application makes use of an oscillating mirror to effect the scanning or sweeping action of the beam. Thus, in that scanner the beam is directed to an oscillating mirror to sweep the beam through a predetermined arc, with the swept beam being directed straight from the mirror through the short body portion of the housing and out through a window to impinge on a bar code disposed opposite the window.
Examples of other hand-held laser scanners have been disclosed in the following patent literature: U.S. Pat. Nos. 4,387,297 (Swartz et al.), 4,409,470 (Shepard et al), 4,460,120 (Shepard et al.), 4,607,156 (Koppenall et al.) and 4,760,248 (Swartz et al).
While the devices disclosed in the aforementioned prior art all exhibit the characteristic of being compact (to some degree) in the interest of operator ease of use, nevertheless all still leave something to be desired from the standpoint of size.
In my copending U.S. patent application Ser. No. 07/299,998, filed on Jan. 23, 1989, entitled Laser Scanner Engine with Folded Beam Path, which is assigned to the same assignee as this invention and whose disclosure is incorporated by reference herein, there is disclosed and claimed a modular scanning engine which is extremely compact in size and suitable for use in various types of scanning systems.